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Dry Creek Fish Habitat Enhancement Feasibility Study Current Conditions Summary .
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Dry Creek Fish Habitat Enhancement Feasibility StudyCurrent Conditions Summary
Dry Creek Fish Habitat Enhancement-Component of Russian River Instream Flow and Restoration (Biological Opinion)- Habitat enhancement for coho salmon and steelhead trout- Opportunity: abundant cool water in late summer
Habitat Enhancement Feasibility Study-Two Study Phases1) Inventory of Current Conditions▪ Watershed Characteristics/History▪ Stream Geomorphology Today▪ Fish Habitat 2) Feasibility Analysis and Conceptual Design
Watershed Characteristics-217 sq. mi. (130 sq. mi. upstream of Warm Springs Dam)- Largest tributary to Russian River based on annual runoff- Creek flow pattern pre-Warm Springs Dam ▪ Typical of Mediterranean Climate ▪ High floods resulting from winter rainstorms ▪ Very low flow (dry in many years) in summer
Watershed History1850s: Valley settled▪ 40% of forested acres cleared 1850-1870 ▪ Increased runoff and sediment to lower valley ▪ These actions initially raised creek bed (3’) ▪ Vegetation recovery resulted in creek bed lowering by turn of century (4’) 1900 – 1970s: Gravel mining in Russian River 1950s -1970s: Gravel mining in Dry Creek near Westside Br. 1952: Healdsburg Dam 1959: Coyote Dam▪ Combined influences resulted in additional creek bed lowering by (10’) ▪ Lowering of stream propagated up Dry Creek tributaries ▪ Effects slowed by mid-1980s
Watershed History Creek changes 1850 -1980s Vineyard level 1850 Vineyard level Vineyard level Pre dam conditions
Watershed History Creek changes 1984 – Today1984: Closure of Warm Springs Dam▪ flow patterns ▪ sediment patterns ▪ vegetation patterns
Stream Geomorphology TodayFlow patterns:▪ reduced winter floods ▪ higher summer flowsSediment patterns:▪ cut off upper 60% of watershed ▪ moderated by supply from Pena, Dutcher, Crane, Mill Creeks
Stream Geomorphology TodayVegetation patterns:▪ combination of reduced winter floods and high summer flows resulted in extensive riparian growth ▪ stabilizes gravel bars ▪ focuses flow in channel
Fish HabitatInventory of 13.9 miles between WS dam and Russian River:▪ Pools ▪ Riffles ▪ Glides ▪ Alcove and edge habitat
Fish HabitatInventory of 13.9 miles between WS dam and Russian River: ▪ Measured depths, widths, areas, cover, complexity, creek bed material, woody material▪ Created maps for each segment of study reach (16 sub-reaches)
Fish HabitatSelected Results (substrate and woody material):▪ Riffles had 80% of their gravels in target range for spawning ▪ Fine sediment in riffles low (<10%) ▪ Average of 209 pieces of woody debris per mile (pools, scour pools) ▪ 46% of woody debris pieces were living ▪ Alcoves most prevalent in lower half of study reach ▪ Edge habitat slightly more prevalent in lower half ▪ Overall habitat quality less than ideal, e.g., velocity
Opportunities for Fish Habitat EnhancementAreas of interest for potential habitat enhancement identified ▪ Abundant opportunities for enhancement of pools, riffles, stream banks and creation of off-channel habitats ▪ All areas of interest within historic channel
Opportunities for Fish Habitat EnhancementPotential enhancement applications ▪ Riffles – supplement gravel to increase area ▪ Pools – add/re-arrange woody materials to increase cover and complexity
Opportunities for Fish Habitat EnhancementPotential enhancement applications▪ Off-channel and alcove habitat creation Before After After
Opportunities for Fish Habitat EnhancementPotential enhancement applications ▪ Stream banks – stabilization to enhance cover and complexity Dry Creek After Before
Next StepsDetailed Feasibility Analysis and Concept Designs ▪ System-scale feasibility ▪ Project-scale feasibilityUpcoming Schedule ▪ Spring – summer 2010: Detailed feasibility analysis ▪ Fall 2010: Concept designs and ranking of opportunities ▪ Summer 2011: Pilot project implementation
Questions?Dry CreekFish Habitat Enhancement Feasibility StudyCurrent Conditions Summary